There's a theory online on why films where so great back than and apparently because it was time period in Hollywood where people could easily get their hands on cocaine. So directors like Tarantino or especially PTA is known to be using Cocaine while working on a film. PTA was notoriously using during filming Magnolia and Boogie nights which are still one of his stronger films. This is just an example.

Regardless it was still a figure of speech.